Should we put requirements on prerequisites in a common place? (was ACTS-225)

Original author Christian Gumpert @cgumpert

At the moment, each CMakeLists specifies the required version of its dependencies individually. This leads to varying requirements which make it difficult to determine which versions of the dependencies are actually required to have all components of ACTS working properly.

Should we therefore specify in all required versions in a central place? This would simplify the management of dependencies. The downside of course is that we couple the dependencies of possibly independent packages.